In
1828 at several locations in the french-swiss border region of the Jura mountain
chain there were found populations of a pale violet flowered butterwort, that
caused some confusion. First considered as P. longifolia, then several
times described as a distinct species, but finally in 1962 ranked by Casper as
a colour mutant of the ordinary P. grandiflora ssp. grandiflora under the
denomination f. pallida (engl.: of a pale
colour).
Only
few populations of P. grandiflora f. pallida do occur in a restricted area
of the Haut-Jura mountains (northwest facing slopes above and below of Col de
la Faucille). The plants grow either in young eroded limestone soils (often slightly
shaded by grasses) or at shady places in mainly conifer forests, whereas the soil
is richer in organic matter. At the latter location also populations of P.
grandiflora ssp. grandiflora can be found, but never get mixed with the f.
pallida populations (which indicates, that the f. pallida populations
should be homozygous for the gene locus of the colour mutation).
P.
grandiflora f. pallida differs from P. grandiflora ssp. grandiflora
by its pale violet coloured corolla lobes, by its dark violet venation of the
throat and by the very thick and cylindrical spur.
Plants
of P. grandiflora ssp. grandiflora that grow at the same location:
Pinguicula
grandiflora f. pallida (Gaudin) Casper (1962)
